1) General subject: the fact is that, the fact is that (...) (...), the matter is (the point is), the point is that, the question is, the thing is, the truth is that, the fact of the matter is, the problem is, thing is, specifically
2) Diplomatic term: the case is that
3) Politics: the point is that
4) Makarov: as it happens, point is, the point is
Универсальный русско-английский словарь. Академик.ру. 2011.